DC Leaks site was initially registered by THCServers, a company that has only been the initial registrar for 14 sites since 2013. Including DC Leaks, three of those sites have been connected to the Russian hackers believed to be behind the DNC hack, including a site identified by the German government.
The Russian hackers, nicknamed Fancy Bear, have a pattern of using domain registrars outside of United States that accept bitcoin and the Romanian THCServers fit the mold. It is registered to an email account from europe.com, which, like most of the emails connected to FancyBear, is a free web service based in Europe.
A representative from ThreatConnect, the company that linked Fancy Bear to DCLeaks, noted that the obscure Romanian THCServer and Europe.com would be abnormal for an American hacktivist collective, and believes the sum-total is a strong circumstantial case.